HYDRO24780

• Permit No: M1977378
• IBM Index Class Name: Hydrology
• Doc Date: 10/25/2004
• Doc Name: Requested Docs. on the Bulkhead at the Mogul Mine.
• From: DMG
• To: Rob Robertson-BLM and Andrew Ross-WQCD
• Media Type: D
• Archive: No

project Design Mogul Tunnel Bulkhead
10.6' x 9.5' (9' Thick, Station 2+411
References used•
By JFA Date 8/21/03
Sheet 1 of 6
Calculations are based on:
Abel, J.F., Jr., Bulkhead desim for acid mine drainaee: 1998, in Proc Wcestern U.S. Mining-Impacted Watersheds,
Joint Conf on Remediation and Ecological Risk Assesment Technologies, Denver, CO, 36 p
American Concrete Institute, 1995, Building code requirements for strucbtral concrete (ACI 318-95) and
commentary -ACI 318R-95:369 p
Wang, C.K. 8c C.G. Salmon, 1985, Reinforced concrete design, 4th ed, Harper & Rowe Publishers, Inc.
Notation•
a =minimum concrete compression wne
depth (in) to balance rebaz tension
I11pntS:
Beam width, b w := 1 ft
Bulkhead depth below surface, B d := 137 ft
A , = azea of rebaz (in3)
bW =beam width (1-ft)
B p =allowable breakdown pressure (psi)
d = max distance compressive £ber to rebaz
center (in)
E ba, =earthquake bulkhead mass (lb)
E ~„ =earthquake static fluid load (Ib)
f~~ =concrete tensile strength [3(f~trz]
f C9 =concrete shear strength [2(f~)t~)
FS = factor of safety
L =bulkhead (beam) thickness (ft)
L a =bulkhead shear thickness (ft)
I =moment of inertia (in4)
M =beam bending moment (ft-lb)
M„ =factored beam bending moment (ft-Ib)
M„ =nominal beam bending moment (ft-lb)
M 18 =earthquake beam bending moment (ft-lb)
p =maximum hydraulic pressure head (psi)
pW = ratio of tensile reinforcement
S =section modulus (n3)
T =tensile bending force (lb/ft)
U =factored required strength (Ib/ft)
U a =earthquake required strength (ib/ft)
V =concrete shear strength (Ib/ft)
Maximum tunnel height, h ~ 9.5 ft
Maximum tunnel width, 1 := 10.6 ft
Design water head H := 218 ft
Concrete compressive strengttt,c := 3000 psi
Inbye line of sight water distance$ ]s := 420 ft
Overburden rock density, y r := 169.4 pcf
Concrete density, q c := 150 pcf
Water density, y w := 62.4 pcf
Minimum concrErte rebaz cover,m o := 3.5 in
Rebaz yield strength, f y := 60000 psi
Allowable pressure gradient with pressure
p := 41 psi
grouting of bulkhead/rock t:ontact,
Gravity acceleration, g := 32.2 ftlsecz
Maximum credible earthquake acceleratioq := 0.094 •g
Bulkhead trial thickness, L t := 9 ft
Strength reduction factors
Rebar flexural (ensile strength, ~ rt ;= 0.90
Rebaz reinforced concrete sheaz, ~ ~ := 0.85
Plain concrete fler:ure strength, ~ ~ := 0.65
Reinforced concre4e flexural strength,¢ rc ~ 0.85